Revert "Update dependency org.springframework.boot:spring-boot-starter-parent to v2.6.1 (#236)" (#242)
Revert "Update dependency org.springframework.boot:spring-boot-starter-parent to v2.6.1 (#236)" (#242)

This reverts commit 0f63c3d3fe3dbc16bd72f7823f142bcf4c2fc2d0.
GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples